In the Greco-Roman world, ecclesia (Greekἐκκλησίᾱ, ekklēsiā (Latinecclesia) meaning "congregation, church") was used to refer to a lawful assembly, or a called legislative body. As early as Pythagoras, the word took on the additional meaning of a community with shared beliefs.[1] This is the meaning taken in the Greek translation of the Hebrew Scriptures (the Septuagint), and later adopted by the Christian community to refer to the assembly of believers.[2]

Ecclesiastical provinces first corresponded to the civil provinces of the Roman Empire. From the second half of the second century, the bishops of these provinces were accustomed to assemble on important occasions for common counsel in synods. From the end of that century the summons to attend these increasingly important synods was usually issued by the bishop of the capital or metropolis of the province, who also presided over the assembly, especially in the East. Important communications were also forwarded to the bishop of the provincial capital to be brought to the notice of the other bishops. Thus in the East during the third century the bishop of the provincial metropolis came gradually to occupy a certain superior position, and received the name of metropolitan.

At the First Council of Nicaea (325) this position of the metropolitan was taken for granted, and was made the basis for conceding to him definite rights over the other bishops and dioceses of the state province. In Eastern canon law since the fourth century (cf. also the Synod of Antioch of 341, can. ix), it was a principle that every civil province was likewise a church province under the supreme direction of the metropolitan, i.e. of the bishop of the provincial capital.

This division into ecclesiastical provinces did not develop so early in the Western Empire. In North Africa the first metropolitan appears during the fourth century, the Bishop of Carthage being recognized as primate of the dioceses of Northern Africa; metropolitans of the separate provinces gradually appear, although the boundaries of these provinces did not coincide with the divisions of the empire. A similar development was witnessed in Spain, Gaul, and Italy. The migration of the nations, however, prevented an equally stable formation of ecclesiastical provinces in the Christian West as in the East. It was only after the fifth century that such gradually developed, mostly in accordance with the ancient divisions of the Roman Empire. In Italy alone, on account of the central ecclesiastical position of Rome, this development was slower. However, at the end of Antiquity the existence of church provinces as the basis of ecclesiastical administration was fairly universal in the West. In the Carolingian period they were reorganized, and have retained their place ever since.

Historical development of ecclesiastical provinces in the Eastern Orthodox Church was influenced by strong tendencies of internal administrative centralization. Since the First Ecumenical Council (325), the Archbishop of Alexandria was given supreme jurisdiction over all provinces of Egypt. Similar authority was also granted to Archbishop of Antioch regarding jurisdiction over provinces of Orient. Since the Fourth Ecumenical Council (451), Patriarch of Constantinople was given right to consecrate metropolitan bishops in all regions that were placed under his supreme jurisdiction.[3] In time, previous administrative autonomy of original ecclesiastical provinces was gradually and systematically reduced in favor of patriarchal centralization. Ancient practice of annual councils of provincial bishops, headed by their local metropolitans, was also abandoned in favor of centralized councils, headed by patriarchs and attended by metropolitan bishops.

Creation of new autonomous and autocephalous jurisdictions was also marked by tendencies of internal centralization. The newly created Archbishopric of Ohrid (1018) was structured as a single ecclesiastical province, headed by archbishop who had jurisdiction over all of his suffragan bishops. In 1219, autocephalous Serbian Orthodox Church was also organized as one ecclesiastical province, headed by archbishop with direct jurisdiction over all Serbian bishops.[4] By the end of Middle Ages, each autocephalous and autonomous church in Eastern Orthodoxy was functioning as a single, internally integrated ecclesiastical province, headed by local patriarch or archbishop.

Only in modern times, some Eastern Orthodox Churches have revived the ancient practice by creating internal ecclesiastical provinces on the middle (regional) level of church administration. In Romanian Orthodox Church there are six regional metropolitanates, headed by local metropolitans who are presiding over regional synods of local bishops, and have special duties and privileges. For example, Metropolitan of Oltenia has regional jurisdiction over four local dioceses. On the other hand, majority of Eastern Orthodox Churches remain to function as highly centralized church bodies, each of them functioning as a single ecclesiastical province.[5]

The authority of a Latin-Church metropolitan over the other sees within his province is now very limited. During a vacancy in a suffragan see, the metropolitan is to name a temporary diocesan administrator if the College of Consultors of the diocese fails to elect one within the prescribed period.[6] A metropolitan generally presides at the installation and consecration of new bishops in the province, and the tribunal of the metropolitan see generally serves as the first court of appeal regarding canonical matters of provincial diocesan tribunals. The metropolitan's insignia is the pallium. The article in the Catholic Encyclopedia of 1911 on "metropolitan" shows that the metropolitan then had scarcely any power more than now.[7]

The borders of provinces have often been inspired, or even determined, by historical or present political borders; the same is often true of diocesan borders within a province. The following are some examples:

In France, where the boundaries partly reflected later Roman provinces, most have been rearranged (2002) to fit new administrative regions.

A comparable process to that of France occurred earlier in Spain.

In southern Germany, the diocesan boundaries follow the political boundaries that existed between 1815 and 1945.

In Scotland, the dioceses, and subsequently the two provinces, follow both civil and geographical boundaries such as rivers.

In geographically large nations with a sizeable Catholic population, such as the United States, ecclesiastical provinces typically follow statelines, with less populous states being grouped into provinces. In the United States, there are five exceptions:

Many countries contain more than one province, except those with a small population or few Catholics.

In at least one case, a province contains dioceses that are in more than one nation, e.g., the Province of Samoa-Apia, of which the metropolitan see (the Archdiocese of Samoa-Apia) is in the Independent State of Samoa, and its only suffragan see (the Diocese of Samoa-Pago Pago) is in American Samoa (an unincorporated territory of the United States). Even individual dioceses, let alone ecclesiastical provinces, con comprise more than one state: examples are San Marino-Montefeltro (San Marino and part of Italy), Urgell (Andorra and part of Spain, and the Diocese of Rome itself (Vatican City and part of Italy).

The Evangelical State Church in Prussia, formed in 1821 (renamed: Evangelical State Church in Prussia's older Provinces in 1875, Evangelical Church of the old-Prussian Union in 1922), had ecclesiastical provinces (Kirchenprovinz[en]) as administrative subsections mostly following the boundaries of those political Provinces of Prussia which formed part of the state before 1866, with some border changes after 1920 following WWI territorial cessions.

The term province, or occasionally religious province, also refers to a geographical and administrative subdivision in a number of orders and congregations. This is true of most, though not all, religious communities founded after the year AD 1000, as well as the Augustinians, who date from earlier.

A province of a religious institute is typically headed by a provincial superior. The title differs by each institute's tradition (provincial minister for Franciscans; provincial prior for Dominicans; provincial for the Augustinians, simply "provincial" or "provincial father" for the Jesuits and many others, for instance).

The borders of a religious institute's provinces are determined independently of any diocesan structure, and so the borders often differ from the 'secular', or diocesan, ecclesiastical provinces. The orders' provinces are usually far larger than a diocese, a secular province, or even a country, though sometimes they are smaller in an institute's heartland.

Most monastic orders are not organized by provinces. In general, they organise their administration through autonomous houses, in some cases grouped in larger families. For example, each Benedictineabbey is an independent foundation, but will often choose to group themselves into congregations based on historical connections.